i have a 1990 formula with a 305 TBI and a 700R4, this winter i am rebuilding a 454 to give my baby some new muscle. But, unfortuantely i know that the r4 thats in it now will not last very long because this motor will have between 500-600 horse. I was thinking that maybe the 4L60E out of a Z28 would be decent enough to hammer on, since they are building a drag track not 15 minutes away from my town im gonna need a better tranny. I do want to keep my overdrive, so what about a Turbo 400 with maybe an aftermarket overdive unit, ive seen them before i just cant remeber where. anyways, any help is much appreciated.

 

The 4l60e is basically a 700r4 with electronics. The 4l65 is stronger, in late model trucks. A Th400 is alot stronger, and I've heard the Gear Vendors O.D. unit can take a lot of power.

 

I think that would want the 4l80E, that is the beefy overdrive put into trucks, IIRC. If you have the cash, go for the th400 w/ the overdrive unit. I saw a guy race with one of the overdrives on a th350. Its like the motor never left it peak, he went 1, 1OD, 2, 2OD, 3, 3OD. It sounded cool as hell too. He said that it eliminates that middle point between gears completely, you just have to practice to get it right. But its expensive. I am going to go this route with my th350 someday, I think it would be neat to try.

 

A TH400 and a 4L80E are basically the same transmission, the 4L80 is just electronically controlled with an added overdrive gear. 700R4s can easily be biult to handle 5-600 hp and are a lot lighter/more efficient than TH400s and the other heavy-duty GM transmissions. If I was you, I would look in to rebiulding the 700R4 with quality parts and saving some money/headache. The aftermarket for the 700s is growing, you'd be suprised what is out there and what they can handle.

 

Are you sure about being able to build up an R4 to handle the torque of a big block, when the first R4's came out they wouldnt even shift brand new. I dont mind the challenge of fitting a turbo 400 in my 3rd gen.

 

The 700 can be built to withstand it, for about 3 times as much as the 400.

 

its not that hard of a challenge honestly

heres a kit to look at
http://www.bulkpart.com/Merchant2/me...Category_Code=

this will allow you to retain your factory torque arm mount by reusing your factory 700r4 tail shaft so you wont have any speedo problems ...

 

The 700 has MANY advantages over the 400. The biggest of which, is it's lighter and uses a hell of a lot less torque to run. IF this guy really has 5-600 hp he can easily biuld the 700R4 to handle it, and he'll still have overdrive. That means more gear and lighter internals.

Go with Kelvlar clutches, 2-4 band, 5 pinion planetaries, Larger servo kit, 10 vane front pump, and a pressure boost valve and you should be in great shape.

Stock for stock the 400 is superior, but the 700 is WAY more streetable and is already in the car, so why not biuld it out. The things listed would be in the 500 dollar range if you shop around and the way I see it, it would result in a much more drivable and enjoyable car.

This is just mt opinion, and I'm the same person who ran a lincoln locked 7.625" 10 bolt into the 11's, so spend your money where you want, I'll spend mine on my happiness. Just my

 

If you plan to drag race the car, the gear spread of the 700 is kinda close togther, but it certainly can be built to withstand a 600 HP big block. If you want to learn more, you can go to

www.700r4.com
They do performance rebuilds and make swap-in kits for GM Autos.

 

that kit previously mentioned, it says its for blazers and pickups. Nothing about srd gen or is it pretty much universal?

 

yes its universal it takes the tail shaft housing from the 700r4 and installs it on a th400 with a spacer block then you can run the factory torque arm mount on your tailshaft and speedo from the 700r4 tailshaft is reused....simple

heres a pic of one of those kits on my brothers th350 we put in his car this summer

 

This is pretty much a matter of personal opinion. I see it like this:

Overdrive means nothing to me. Wont use it in the 1/4, wont use it driving around town. If I want to hit the highway, I drive my mileage ****, a bonneville. When you get to a certain point, the car isnt a highway cruiser anymore anyway, who needs it? I cant justify the spending of over 1000 bucks on a 700r4, when I can get a TH350 for 600, that can handle just as much. Thats just me. With the new kits that they sell nowadays, the th350 bolts in just as easy as a 700r4.

That picture below, BTW, is my trans. With that kit, it was just like bolting up a 700r4.

 

I'm with you on this one. I have a 2004R in my 68 bird that I did that too, along with a couple other things. I'll never build another car without overdrive again. It's all well and good to say you won't drive it, but, after spending every last dime on the car it's nice to know you can take it anywhere if the mood strikes. CK performance in NY makes all sorts of stuff. If you want I'll go dig up the link somewhere. And for the record, I have a 4,200 stall vigilante with the lockup feature. Yet another way to make a built car and tranny streetable enough to drive to florida from Mass, which I've done, twice... In the end, I think it's worth every penny.
BTW, that's a neat adapter kit, never seen those before. And on the gear vendors, they replace the tailshaft of the tranny so you're on your own when it comes to mounting the torque arm.

 

You'll need more than just what was mentioned above if you want your 700R4 to handle big block torque.. You'll need, well, here, read this:

http://www.torquedriveinc.com/

 

i said before though that im not really interested in keeping the 700 r4, id feel better just having a heavy duty trans from the start with and aftermarket overdrive unit.

 

Just keep in mind, like I said, you'll need to figure out another way to mount the torque arm. And, a gear vendors adds a fair amount of length to the tranny so your average aftermarket arm may not clear it... Food for thought....

 

I am all about overdrive. My camaro had a 700r4 and 410 in it and I loved it. For comparison my brother has a s10 with a th350 and 373s. Fun to about 60. Who wants to cruise the highway at 75 and 3500 rps. My camaro would cruise 75 at 2400 rpms. So overdrive is worth it in my opinion. My brother realized this and now borows my car for any hyw. trip he takes.